docstr: Initialize the random projection matrix.
  
  Parameters
  ----------
  corpus : iterable of iterable of (int, int)
    Input corpus.
docstr_tok: ["Initialize","the","random","projection","matrix",".","Parameters","--","--","--","--","--","corpus",":","iterable","of","iterable","of","(","int",",","int",")","Input","corpus","."]
code: def initialize(self, corpus):
      """Initialize the random projection matrix.
  
      Parameters
      ----------
      corpus : iterable of iterable of (int, int)
        Input corpus.
  
      """
      if self.id2word is None:
          logger.info(
              "no word id mapping provided; initializing from corpus, assuming identity"
          )
          self.id2word = utils.dict_from_corpus(corpus)
          self.num_terms = len(self.id2word)
      elif self.id2word:
          self.num_terms = 1 + max(self.id2word)
      else:
          self.num_terms = 0
  
      shape = self.num_topics, self.num_terms
      logger.info("constructing %s random matrix", str(shape))
      # Now construct the projection matrix itself.
      # Here i use a particular form, derived in "Achlioptas: Database-friendly random projection",
      # and his (1) scenario of Theorem 1.1 in particular (all entries are +1/-1).
      randmat = 1 - 2 * np.random.binomial(
          1, 0.5, shape
      )  # convert from 0/1 to +1/-1
      # convert from int32 to floats, for faster multiplications
      self.projection = np.asfortranarray(randmat, dtype=np.float32)
  
file_path: gensim/gensim/models/rpmodel.py
imports: import logging
  import numpy
  from gensim import interfaces, matutils, utils
label_desc: Use image node_id 3 for calling the RpModel obj's underlying member method code with example usage: obj.initialize(corpus) without return types